Conventionally, it has been required to finish the roundness and cylindricity for processing diameter and shape of a cylinder bore of a cylinder block, for example, with high accuracy as it is a key part for determining engine performance. To this end, a honing method has been generally utilized as a final finish. Japanese Laid-Open Patent Publication No. (Hei) 5-277928 discloses a method for honing an inner surface of a cylinder wherein a bore diameter is continuously measured during processing. The process is completed upon reaching a predetermined bore diameter.
As taught therein, since the method measures the bore diameter during processing, an air micro gauge may be installed as a processing tool within a honing head. Further, as another method of measuring the bore diameter during processing, a plug gauge may be installed in the honing head.